**5. Conclusions**

T2DM is one of the most widely spread metabolic disorders and most often discovered at the step of complications, which makes therapy less efficient and more expensive. HbA1c provides information about changes in glycaemic status over three months, and, hence, is insensitive to short-term glucose fluctuations preceding the disease. In this context, using individual glycation sites as T2DM biomarkers might provide a good solution of this problem. Precise and reliable quantification of glycated peptides is a prerequisite for establishing biomarkers and developing clinical diagnostics of T2DM. Different methods are established and qualified for the quantification of individual glycation sites in plasma proteins using label-free or absolute quantification. Due high precision it is applicable to use in the combination with HbA1c for screening of large patient cohorts for early diagnosis of T2DM, therapy control, sub-typing disease stages, and the prognosis of complication risks. Obviously, the biomarker potential of glycated peptides is still mostly unknown. On one hand, more explorative studies are necessary to discover new biomarker candidates. On the other – these biomarker candidates need to be confirmed in wide-scale screening in large cohorts with reliable absolute quantification methods.
